#![no_main]
#![no_std]

extern crate alloc;
extern crate lang_items;
extern crate libtock_drivers;

use core::fmt::Write;
use libtock_console::{Console, ConsoleWriter};
use libtock_runtime::{set_main, stack_size, TockSyscalls};

stack_size! {0x4000}
set_main! {main}

type Syscalls = TockSyscalls;

#[cfg(not(feature = "with_nfc"))]
mod example {
    use super::{ConsoleWriter, Syscalls, Write};

    pub fn nfc(console: &mut ConsoleWriter<Syscalls>) {
        writeln!(console, "NFC feature flag is missing!").unwrap();
    }
}

#[cfg(feature = "with_nfc")]
mod example {
    use super::{Console, ConsoleWriter, Write};
    use crate::Syscalls;
    use libtock_drivers::nfc::{NfcTag, RecvOp};
    use libtock_drivers::result::{FlexUnwrap, TockError};
    use libtock_drivers::timer;
    use libtock_drivers::timer::{Timer, Timestamp};
    use libtock_platform::{DefaultConfig, ErrorCode};

    #[derive(Copy, Clone, Debug, PartialEq)]
    #[allow(clippy::upper_case_acronyms)]
    enum ReturnCode {
        /// Operation completed successfully
        SUCCESS,
        /// Generic failure condition
        FAIL,
        /// Underlying system is busy; retry
        EBUSY,
        /// The component is powered down
        EOFF,
        /// An invalid parameter was passed
        EINVAL,
        /// Operation canceled by a call
        ECANCEL,
        /// Memory required not available
        ENOMEM,
        /// Operation or command is unsupported
        ENOSUPPORT,
    }

    impl From<ErrorCode> for ReturnCode {
        fn from(original: ErrorCode) -> ReturnCode {
            match original {
                ErrorCode::Fail => ReturnCode::FAIL,
                ErrorCode::Busy => ReturnCode::EBUSY,
                ErrorCode::Off => ReturnCode::EOFF,
                ErrorCode::Invalid => ReturnCode::EINVAL,
                ErrorCode::Cancel => ReturnCode::ECANCEL,
                ErrorCode::NoMem => ReturnCode::ENOMEM,
                _ => ReturnCode::ENOSUPPORT,
            }
        }
    }

    /// Helper function to write on console the received packet.
    fn print_rx_buffer(buf: &mut [u8]) {
        if let Some((last, bytes)) = buf.split_last() {
            let mut console = Console::<Syscalls>::writer();
            write!(console, "RX:").unwrap();
            for byte in bytes {
                write!(console, " {:02x?}", byte).unwrap();
            }
            writeln!(console, " {:02x?}", last).unwrap();
        }
    }

    /// Function to identify the time elapsed for a transmission request.
    fn bench_transmit(
        console: &mut ConsoleWriter<Syscalls>,
        timer: &Timer<Syscalls>,
        title: &str,
        buf: &mut [u8],
    ) -> ReturnCode {
        let amount = buf.len();
        let start =
            Timestamp::<f64>::from_clock_value(timer.get_current_counter_ticks().flex_unwrap());
        match NfcTag::<Syscalls, DefaultConfig>::transmit(buf, amount as u32) {
            Ok(_) => (),
            Err(TockError::Command(ErrorCode::Cancel)) => return ReturnCode::ECANCEL,
            Err(_) => writeln!(console, " -- tx error!").unwrap(),
        }
        let end =
            Timestamp::<f64>::from_clock_value(timer.get_current_counter_ticks().flex_unwrap());
        let elapsed = (end - start).ms();
        writeln!(
            console,
            "{}\n{:.2} ms elapsed for {} bytes ({:.2} kbit/s)",
            title,
            elapsed,
            amount,
            (amount as f64) / elapsed * 8.
        )
        .unwrap();

        ReturnCode::SUCCESS
    }

    fn receive_packet(console: &mut ConsoleWriter<Syscalls>, buf: &mut [u8; 256]) -> ReturnCode {
        match NfcTag::<Syscalls, DefaultConfig>::receive(buf) {
            Ok(RecvOp {
                recv_amount: amount,
                ..
            }) => {
                if amount <= buf.len() as u32 {
                    print_rx_buffer(&mut buf[..amount as usize]);
                }
            }
            Err(TockError::Command(code)) => return code.into(),
            Err(_) => {
                writeln!(console, " -- RX Err").unwrap();
                return ReturnCode::ECANCEL;
            }
        }
        ReturnCode::SUCCESS
    }

    fn transmit_reply(
        console: &mut ConsoleWriter<Syscalls>,
        timer: &Timer<Syscalls>,
        buf: &[u8],
    ) -> ReturnCode {
        let mut return_code = ReturnCode::SUCCESS;
        match buf[0] {
            0xe0 /* RATS */=> {
                let mut answer_to_select = [0x05, 0x78, 0x80, 0xB1, 0x00];
                return_code = bench_transmit(console, timer, "TX: ATS", &mut answer_to_select);
            }
            0xc2 /* DESELECT */ => {
                // Ignore the request
                let mut command_error = [0x6A, 0x81];
                return_code = bench_transmit(console, timer, "TX: DESELECT", &mut command_error);
            }
            0x02 | 0x03 /* APDU Prefix */ => match buf[2] {
                // If the received packet is applet selection command (FIDO 2)
                0xa4 /* SELECT */ => if buf[3] == 0x04 && buf[5] == 0x08 && buf[6] == 0xa0 {
                    // Vesion: "FIDO_2_0"
                    let mut reply = [buf[0], 0x46, 0x49, 0x44, 0x4f, 0x5f, 0x32, 0x5f, 0x30, 0x90, 0x00,];
                    return_code = bench_transmit(console, timer, "TX: Version Str", &mut reply);
                } else if (buf[6] == 0xd2 && buf[7] == 0x76) || (buf[6] == 0xe1 && (buf[7] == 0x03 || buf[7] == 0x04)){
                    let mut reply = [buf[0], 0x90, 0x00];
                    return_code = bench_transmit(console, timer, "TX: 0x9000", &mut reply);
                } else /* Unknown file */ {
                    let mut reply = [buf[0], 0x6a, 0x82];
                    return_code = bench_transmit(console, timer, "TX: 0x6A82", &mut reply);
                }
                0xb0 /* READ */ =>  match buf[5] {
                    0x02 => {
                        let mut reply = [buf[0], 0x12, 0x90, 0x00,];
                        return_code = bench_transmit(console, timer, "TX: File Size", &mut reply);
                    }
                    0x12 => {
                        let mut reply = [buf[0], 0xd1, 0x01, 0x0e, 0x55, 0x77, 0x77, 0x77, 0x2e, 0x6f, 0x70, 0x65,
                        0x6e, 0x73, 0x6b, 0x2e, 0x64, 0x65, 0x76, 0x90, 0x00,];
                        return_code = bench_transmit(console, timer, "TX: NDEF", &mut reply);
                    }
                    0x0f => {
                        let mut reply = [buf[0], 0x00, 0x0f, 0x20, 0x00, 0x7f, 0x00, 0x7f, 0x04, 0x06, 0xe1, 0x04,
                        0x00, 0x7f, 0x00, 0x00, 0x90, 0x00,];
                        return_code = bench_transmit(console, timer, "TX: CC", &mut reply);
                    }
                    _ => {
                        let mut reply = [buf[0], 0x90, 0x00];
                        return_code = bench_transmit(console, timer, "TX: 0x9000", &mut reply);
                    }
                }
                _ => {
                    let mut reply = [buf[0], 0x90, 0x00];
                    return_code = bench_transmit(console, timer, "TX: 0x9000", &mut reply);
                }
            }
            0x26 | 0x52 | 0x50 /* REQA | WUPA | Halt */ => {
                return ReturnCode::EOFF;
            }
            _ => (),
        }
        return_code
    }

    pub fn nfc(console: &mut ConsoleWriter<Syscalls>) {
        // Setup the timer with a dummy callback (we only care about reading the current time, but the
        // API forces us to set an alarm callback too).
        let mut with_callback = timer::with_callback(|_| {});

        let timer = with_callback.init().flex_unwrap();

        writeln!(console, "Clock frequency: {:?} Hz", timer.clock_frequency()).unwrap();

        let mut state_change_counter = 0;
        loop {
            let mut rx_buf = [0; 256];
            match receive_packet(console, &mut rx_buf) {
                ReturnCode::EOFF => {
                    // Not configured
                    while !NfcTag::<Syscalls, DefaultConfig>::enable_emulation() {}
                    // Configure Type 4 tag
                    while !NfcTag::<Syscalls, DefaultConfig>::configure(4) {}
                }
                ReturnCode::ECANCEL /* field lost */ => {
                    NfcTag::<Syscalls, DefaultConfig>::disable_emulation();
                }
                ReturnCode::EBUSY /* awaiting select*/ => (),
                ReturnCode::ENOMEM => {
                    writeln!(console, " -- Amount more than buffer limit").unwrap()
                }
                ReturnCode::FAIL => writeln!(console, " -- Invalid CRC").unwrap(),
                ReturnCode::EINVAL /* covered in driver interface */ => (),
                ReturnCode::ENOSUPPORT => (),
                ReturnCode::SUCCESS => {
                    // If the reader restarts the communication then disable the tag.
                    match transmit_reply(console, &timer, &rx_buf) {
                        ReturnCode::ECANCEL | ReturnCode::EOFF => {
                            if NfcTag::<Syscalls, DefaultConfig>::disable_emulation() {
                                writeln!(console, " -- TAG DISABLED").unwrap();
                            }
                            state_change_counter += 1;
                        }
                        _ => (),
                    }
                }
            }
            if state_change_counter > 100 {
                break;
            }
        }
    }
}

fn main() {
    let mut console = Console::<Syscalls>::writer();
    writeln!(console, "****************************************").unwrap();
    writeln!(console, "nfct_test application is installed").unwrap();
    example::nfc(&mut console);
    writeln!(console, "****************************************").unwrap();
}
